The Philadelphia HIV Therapeutic and Prevention Clinical Trials Unit (Philadelphia HIV CTU-PHCTU) will provide the administrative infrastructure and scientific leadership to advance the science of HIV treatment and prevention within the five proposed HIV Research Networks, Adult Therapeutics, Therapeutics in Pediatric and Maternal Populations, Integrated Prevention, Vaccines, and Microbicides through four specific research aims: Specific Aim 1. Participate in the creation and implementation of the scientific agenda of the HIV Research Networks through committee and protocol team membership and through initiation of new Network science. Specific Aim 2. Participate in the implementation of the scientific agenda of the HIV Research Networks through the cost efficient conduct of clinical trials. Specific Aim 3. Train and mentor the next generation of HIV investigators. By engaging fellows and junior faculty in protocol development, educational conferences and clinical trials, the PHCTU will actively recruit and train the next generation of HIV investigators. Specific Aim 4. Educate the Philadelphia medical, scientific and HIV-affected communities about advances in HIV therapy and prevention. The Philadelphia HIV CTU will help to coordinate and advertise the HIV-related medical and scientific forums that currently exist, and will continue to seek input from the HIV-affected community through its Community Advisory Board and through educational outreach to HIV affected groups. The Philadelphia HIV CTU will feature an integrated, efficient clinical trials structure with four clinical research sites, three on the University of Pennsylvania (University of Pennsylvania Perelman School of Medicine-PSOM and The Children's Hospital of Philadelphia- CHOP) medical campus and one on the Drexel University medical campus, including two sites that will focus on adult HIV therapeutic trials, one that will focus on adult prevention trials, and one that will focus on trials involving pediatric ad adolescent populations.